The objective of the proposed work is: To define the mechanical characteristics of gastrointestinal and genitourinary spincters by determining their pressure-diameter, length-force and stress-strain relationships. To determine the mechanism by which surgical corrective measures, such as fundoplication, modify the length-tension characteristics of the lower esophageal sphincter. To study the effect of pharmachologic, hormonal and electrical stimulation, and age related changes, on mechanical characteristics of gastrointestinal and genitourinary tract.